Emerson Process Management ControlWave EFM 3808 - Manual (Page 233)

CI-ControlWave EFM Appendix F / F- 33
If the Base Pressure or Base Temperature differ from Standard conditions (14.73 psia, 60
ºF) and the 1992 AGA3 calculation is in use, an AGA8 Detail or AGA8 Gross module will be
executed to calculate standard compressibility Zs for the defined gas composition. The
calculation of Zs will be done once per minute or whenever a related gas constant changes.
Users may select which Supercompressibility equation to use on a per run basis. The user
will click on the appropriate button to select the calculation equation to be used. The
selected compressibility calculation will be shown.
Figure F-20 - Supercompressibility Configuration Web Page
When using the AGA8 Gross Calculation, the user must select the Gross Mode1 or the
Gross Mode2 calculation. The user may change the Base Pressure and the Base
Temperature for this screen.
Flowing Static Pressure, Flowing Temperature, BTU and Specific Gravity in use are
displayed on this page.
Values of the gas components used to calculate the Supercompressibility are displayed
along with the FPV, Zflowing and ZBase values calculated by the Supercompressibility
equation in use.